Does the home phone line need 4 wires for phone & ADSL to work ?

Question

Does the home phone line need 4 wires for phone & ADSL to work ?

Answer 1

No.  The phone line running into your house uses only two wires.  The spare pair of wires in the drop cable is used if you have a second line, or in the event that the first pair goes faulty.

In the U.K. system, however, a regular home installation employs three wires between the master jack and any extension jacks.  The third wire is used to carry the ringing separately for historical, technical reasons.   It's usual to connect four wires (white/blue and white/orange pairs) between all the jacks for neatness, but the white/orange wire (terminal 4 on BT-style jacks) is spare.

In the U.S., a single pair of wires is all that is needed to carry the line to each jack.  This will normally be on the red/green pair of wires (or white/blue) with the black/yellow (or white/orange) being a spare pair for a second line etc.